The present invention relates to a cleaning member which is used in, for example, a scrub cleaning process for semiconductor wafers.
FIG. 4 shows a scrub cleaning apparatus for cleaning a surface of a semiconductor wafer W. This cleaning apparatus comprises spin chucks 40 for holding a semiconductor wafer W as an object to be cleaned and subjecting it to rotation, and a cleaning liquid nozzle 43 for supplying a cleaning liquid to a wafer surface to be cleaned. A cylindrical cleaning member 46 is disposed in parallel to the wafer surface by means of a supporting drive member 44. The cylindrical cleaning member 46 is rotated about its axis while the wafer W is rotated, thereby effecting cleaning by scrubbing the wafer surface. During cleaning, the cleaning liquid is supplied from the nozzle 43.
As shown in FIG. 5, the cleaning member 46 comprises a rotary shaft 51 and a cylindrical cleaning element 52 made of sponge and surrounding the rotary shaft 51. Conventionally, in assembling these elements, a lubricant is coated on an inner circumferential surface of the cylindrical cleaning element 52, and the rotary shaft 51, which has a larger diameter than the inner circumferential surface of the cylindrical cleaning element 52, is inserted from one end of the cylindrical cleaning element 52. However, in the cleaning member assembled in the abovementioned manner, the cylindrical cleaning element 52, which is made of sponge, is likely to be subject to undesirable deformation, and in some cases ruptures.
An object of the present invention is to obviate the above-mentioned disadvantage of the conventional cleaning member.
That is, the present invention provides a cleaning member comprising a cylindrical cleaning element having an axial through-hole formed therein and a rotary shaft held in the through-hole with a press-fit. The cylindrical cleaning element is capable of being in either a wet state or a dry state. When the cylindrical cleaning element is separated from the rotary shaft, the through-hole of the cylindrical cleaning element in a wet state has a diameter smaller than a shaft diameter of the rotary shaft and is capable of being enlarged. The cylindrical cleaning element in a dry state is capable of being set in a form such that the through-hole is enlarged. The press-fit of the rotary shaft in the through-hole of the cylindrical cleaning element is performed when the cylindrical cleaning element is in a wet state.
This cleaning member is produced by a method comprising preparing the above-mentioned rotary shaft and cylindrical cleaning element, wetting the cylindrical cleaning element, enlarging the through-hole of the wet cylindrical cleaning element so that it has a diameter larger than the diameter of the rotary shaft, dry-setting the enlarged cylindrical cleaning element, inserting the rotary shaft into the through-hole of the dry-set cylindrical cleaning element, and wetting the cylindrical cleaning element into which the rotary shaft has been inserted to thereby contract the diameter of the through-hole of the cylindrical cleaning element and provide a press-fit between the cylindrical cleaning element and the rotary shaft.
In this method, in order to enlarge the diameter of the cylindrical cleaning element, use is made of a tool for enlarging a diameter of a cylindrical cleaning element. The tool comprises a cylindrical segmented core rod having an axial through-hole formed therein and capable of being diametrically enlarged or contracted. The segmented core rod in a contracted state has a diameter smaller than a predetermined diameter of the cylindrical cleaning element in a wet state A diameter-enlarging element is adapted to be inserted into the through-hole of the segmented core rod so as to enlarge a diameter of the segmented core rod to a diameter larger than the outer diameter of the rotary shaft.
Hereinbelow, the present invention is described, based on embodiments shown in the accompanying drawings.